Energy absorbing structures for passive crash safety are critical to providing occupant protection in the event of a collision. A knee bolster, located at a point lower than the steering wheel and generally on a lower portion of the instrument panel, is designed to absorb the impact on an occupant's knee during a collision event. A knee bolster bracket is a supporting brace for the knee bolster. The knee bolster bracket is designed to yield, or collapse, when it absorbs energy during the collision event to protect the vehicle occupant. Traditional knee bolster bracket designs have “J” or “D” shapes such that there is a single hinge, or trigger, point that collapses upon impact with the occupant's knee, which typically occurs during a frontal crash event. A goal in knee bolster design is to minimize a load on the occupant's knee while maximizing the amount of energy absorbed by the bracket.
Vehicle occupants vary greatly in size and therefore, the knee bolster should be capable of protecting the occupant regardless of their size. For an occupant that is of average size, also known as an occupant in the 50th percentile, the traditional “J” or “D” design is adequate for minimizing load and maximizing energy absorbed. However, for an occupant that is much larger than average (95th percentile) or much smaller than average (5th percentile), the occupant's knee may not contact the knee bolster in an optimal location so as to collapse at the trigger point designed for minimizing load and maximizing energy absorption. Therefore, the traditional design is not as effective for occupants outside of the average size.
There is a need for a knee bolster bracket design that minimizes load for any occupant whose size is between the 5th percentile for females and the 95th percentile for males, maximizes energy absorption for any occupant whose size is between these percentiles and is robust enough to meet stringent crash requirements that are imposed by transportation and safety boards.